Golf clubs and golf club sets

ABSTRACT

A golf club set in which the weight balance of club shafts is optimized for each individual club. The weight balance at the grip-end of the shaft of each of the individual golf clubs increases as the corresponding loft angles of each of the individual golf clubs increase.

TECHNICAL FIELD

[0001] The present invention relates to golf clubs and golf club sets,and more particularly to golf club sets in which the weight balance ofshafts is optimized for each individual club.

BACKGROUND ART

[0002] In recent years, golf clubs have been improved remarkably. Inmany cases, club heads have been designed in order to broaden theirsweet spots or to lower their centers of gravity. For the shafts of golfclubs, new materials are being used to control flexibility or strengthagainst twist.

DISCLOSURE OF THE INVENTION

[0003] According to other features, characteristics, embodiments andalternatives of the present invention which will become apparent as thedescription thereof proceeds below, the present invention provides golfclub sets in which weight balance of the club shafts is optimized foreach individual club.

[0004] According to another embodiment of the present invention, golfclubs are designed so as to produce optimized or improved performcharacteristics for each individual club for golfers of all levels ofexperience, from beginners or novice to professional golfers.

[0005] The present invention is applicable to both woods and irons.

[0006] According to a first aspect of the invention, in golf club sets,the weight balance at the grip-end of the shaft of each of theindividual golf clubs increases as the corresponding loft angle of eachof the individual golf clubs increases.

[0007] According to a second aspect of the invention, golf clubs arecharacterized by controlling the weight balance of the shafts so thatthe weight at the grip-end increases as the loft angles increase.

[0008] Additional objects, advantages and novel features of theinvention will be set forth in the description that follows, and willotherwise become apparent to those skilled in the art upon examinationof the following or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and attained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

[0009] The present invention will be described hereafter with referenceto the attached drawings which are given as non-limiting examples only,in which:

[0010]FIG. 1 is a plan view illustrating an iron set designed accordingto one embodiment of the present invention.

[0011]FIG. 2 is a diagram showing shafts of golf clubs each of which isdivided two regions (A and B) which reference the manner in which theweight balance is regulated according to one embodiment of the presentinvention.

[0012]FIG. 3 is a table showing examples of weight balances between theregions A and B for each club in a set according to one embodiment ofthe present invention.

[0013]FIG. 4 is a plan view illustrating the core of a shaft of a golfclub with a large loft angle, according to another embodiment of thepresent invention.

[0014]FIG. 5 is a diagram showing shafts of golf clubs in a golf clubset according to another embodiment of the present invention.

[0015]FIG. 6 is a table showing examples of diameters at a point A ofshafts according one embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0016] The present invention is directed to golf clubs and golf clubsets, and more particularly to golf club sets in which the weightbalance of shafts is optimized for each individual club. In golf clubsets, each individual club is required to have separate characteristics.That is, it is required, for long (less-lofted) clubs, such as drivers,to effect a long driving distance. On the other hand, shorter(more-lofted) clubs, such as pitching wedges, are required to haveaccuracy both in direction and distance.

[0017]FIG. 1 shows a golf club set to which the present invention isapplied. The golf club set includes a long iron 10 having a small loftangle of θa, a middle iron 20 having a medium loft angle of θb and ashort iron 30 having a large loft angle of θc. The golf club set mayinclude other clubs having different loft angles. In FIG. 1, the loftangles are defined by measuring the angle formed by the central line ofa shaft and the face of a club head.

[0018] In FIG. 1, the long iron 10 includes a head 12 having a face witha loft angle θa, a grip 16 which a player grasps, and a shaft 14 whichconnects the head 12 and the grip 16. In the same manner, the middleiron 20 includes a head 22 having a face with a loft angle θb, a grip 26which a player grasps, and a shaft 24 which connects the head 22 and thegrip 26. The short iron 30 includes a head 32 having a face with a loftangle θc, a grip 36 which a player grasps, and a shaft 34 which connectsthe head 32 and the grip 36. As discussed below, the present inventionoptimizes the weight balance of shafts of golf clubs.

[0019]FIG. 2 shows shafts of golf clubs each of which is divided tworegions (A and B) so as to regulate or reference how the weight balanceis achieved according to one embodiment of the present invention. Asshown in FIG. 2, regions A and B are divided so as to have length ratiosof about 1 to 1.6 from the grip-end of the shaft. In FIG. 2, the regionsA and B are indicated by 14 a and 14 b for a shaft 14 of the long club10. For a shaft 24 of the middle club 20, the regions A and B areindicated by 24 a and 24 b. For a shaft 34 of the short club 30, theregions A and B are indicated by 34 a and 34 b.

[0020]FIG. 3 is a table showing an example of the weight balance(distribution) between the regions A and B of the shaft of each club. Asshown in the table, for the clubs with smaller loft angles, the weightof the region A is set to be lighter and the weight of the region B isset to be heavier as compared to the clubs with larger loft angles. Thisweight balance relationship causes the clubs to feel heavier at thehead-end of the club as compared to the grip-end during a swing. Becausethe mass is increased near the club head, more power can be transferredto the ball at the moment of impact. Therefore, according to the presentinvention, less-lofted clubs can effect longer driving distances.

[0021] For clubs with larger loft angles, the weight of the region A isset to be heavier and the weight of the region B is set to be lighter ascompared to the clubs with smaller loft angles. This weight balancerelationship causes the clubs to feel heavier at the grip-end of theclub as compared to the head-end during a swing. Because the pivot pointof a swing tends to be more stabilized with the weight balance of thepresent invention, it is possible to obtain a more solid impact.

[0022]FIG. 4 shows a core 40 of the shaft of a short club, according toanother embodiment of the present invention. Typically the cores of golfclub shafts for a given set of clubs are designed to have a largerdiameter at the grip-end and a smaller diameter at the head-end. Theshaft cores for longer clubs are designed to be longer than those forshorter clubs. The diameter of the core at the grip-end is designed tobe similar within a given set of clubs. In the same manner, the diameterof the core at the head-end is designed to be similar within a given setof clubs. In other words, the shaft cores of longer clubs are shaped tohave diameters that vary gradually from end to end, because the coresare long. Conversely, the shaft cores of shorter clubs are shaped tohave diameters that vary steeply from end to end, because the cores areshort. In FIG. 4 the thickness of the shaft core, which increasesbeneath grip 40 a can be seen by phantom lines which follow the outersurface of the shaft core.

[0023] According to one embodiment of the present invention, the shaftcore 40 of shorter clubs is shaped to have a larger diameter at thegrip-end so as to increase the weight around the grip-end.

[0024]FIG. 5 is a diagram showing shafts of golf clubs in a golf clubset according to another embodiment of the present invention. As shownin FIG. 5, the diameter at a point A on a shaft 14 (24, 34) iscontrolled for each individual golf club in a golf club set. Accordingto one example, for woods, the diameters at the head-end and grip-end ofclub shafts can be about 8.6 mm and about 15.0 mm, respectively.According to another example, for irons, the diameters at the head-endand grip-end can be about 9.4 mm and about 15.0 mm, respectively.

[0025]FIG. 6 is a table showing examples of diameters at a point A ofshafts according one embodiment of the present invention. In FIGS. 5 and6 point A is three inches away from the head-end of the shaft.Generally, club shafts for a given set of clubs have similar thicknessesmeasured from the outer diameter of the shaft cores and the outerdiameter of the shafts. In this regard, the club shafts typicallyinclude a hollow core element and various layers such as carbon fiberswhich are wound around the core.

[0026] According to the present invention, for shorter clubs(more-lofted clubs), the diameter of the shafts at the point A is set tobe larger. That is, shorter clubs are designed to have shafts with athicker head-end, so that the shaft becomes mechanically stronger. As aresult, such shorter clubs feel more stable to a player before andduring a swing. Conversely, for longer clubs (less-lofted clubs) thediameter of the shafts at the point A is set to be smaller. Accordingly,longer clubs are designed to have shafts with thin head-ends. As aresult, such longer clubs feel more sharp and less stable before andduring a swing.

[0027] Embodiments of the invention exemplified in FIGS. 5 and 6 do nothave to be used to the exclusion of the other embodiments of the presentinvention, because changes in the diameter of the shaft shells do nothave to produce significant effects on the weight of the shafts.Accordingly, changes in the diameters can be accomplished so that theyonly affect the mechanical strength of the shafts. Since shorter clubstend to have heavier heads, such clubs need stronger shafts, especiallyat the head-end.

[0028] According to the embodiments of the present invention which areset forth above, it is possible to design clubs having shafts that areideally or optimally weight balanced according to the skill orexperience of a particular player.

[0029] Although the present invention has been described with referenceto particular means, materials and embodiments, from the foregoingdescription, one skilled in the art can easily ascertain the essentialcharacteristics of the present invention and various changes andmodifications may be made to adapt the various uses and characteristicswithout departing from the spirit and scope of the present invention asdescribed by the claims which follow.

What is claimed:
 1. A golf club set comprising a plurality of individualgolf clubs having progressively increasing loft angles, each golf clubof the set comprising: a grip for grasping the club; a head for hittinga ball; and a shaft connected between the grip and head, each shafthaving a length, a grip-end and a head-end, wherein each shaft has aweight balance at its grip-end thereof which increases from club to clubas the corresponding loft angles of each of the respective clubsincrease.
 2. A golf club set according to claim 1 , wherein the weightbalance of the shaft of each club is controlled by regulating a weightratio between a first and a second region of each shaft, which first andsecond regions divide the shafts lengthwise into two portions havinglength ratios of 1 to 1.6 from the grip-end to the head-end thereof. 3.A golf club set according to claim 2 , wherein a weight ratio betweenthe first and second regions changes in a range of 1:2 to 1:1 as thecorresponding loft angles of each of the individual golf clubs increase.4. A golf club set according to claim 1 , wherein the shaft of each clubincludes a core and the weight balance of the shafts is regulated bycontrolling the thickness of the cores of the shafts.
 5. A golf club setaccording to claim 2 , wherein the shaft of each club includes a coreand the weight balance of the shafts is regulated by controlling thethickness of the cores of the shafts.
 6. A golf club comprising: a gripfor grasping the golf club; a head for hitting a ball, the head having aloft angle; a shaft connected between the grip and head, the shafthaving a grip-end and a head-end; and a weight provided at the grip-endof the shaft which weight provides the shaft with a desired weightbalance, wherein the mass of the weight is proportional to the loftangle.
 7. A golf club according to claim 6 , wherein the weight balanceof the shaft is controlled by regulating a weight ratio between a firstand a second region of the shaft, which first and second regions dividethe shaft lengthwise into two portions having length ratios of 1 to 1.6from the grip-end to the head-end thereof.
 8. A golf club according toclaim 7 , wherein a weight ratio between the first and second regions isa range of 1:2 to 1:1 and varies in this range proportionally to theloft angle.
 9. A golf club according to claim 6 , wherein the shaft hasa core and the weight balance of the shaft is regulated by controllingthe thickness of the core.